Electrical connector

ABSTRACT

A connector for electrically coupling flat ribbon type cables to the edge contacts of printed circuit boards. The connector includes a housing into which the edge of the circuit board having the cable held in proper registry therewith is inserted for engaging a tension band having a cam assembly mounted thereon and causing it to exert a compressive force on the cable and a circuit board to form electrical interconnections therebetween. The connector may also be employed for splicing flat ribbon type cables by using a spacer for holding the cables in proper registry with each other and inserting the spacer and cables into the housing.

United States Patent n91 Cutchaw [451 Feb. 4, 1975 ELECTRICAL CONNECTOR 76 I t I h M'C th 733 E Primary Examiner-Roy Lake 1 men or 'g 52 lrgmla Assistant Examiner-Mark S. Hicks 1 [22] F1 d F b 22 974 Attorney, Agent, or Firm-Herbert E. Haynes, Jr.

1e e 2i] Appl. No.2 444,809 [571 ABSTRACT I A connector for electrically coupling flat ribbon type cables to the edge contacts of printed circuit boards. The connector includes a housing into which the edge [58] i 176 i 176 MP of the circuit board having the cable held in proper l arc 339/17 17 registry therewith is inserted for engaging a tension band having a cam assembly mounted thereon and causing it to exert a compressive force on the cable [56] References cued and a circuit board to form electrical interconnections UNITED STATES PATENTS I therebetween. The connector may also be employed 3,188,598 6/1965 Pferd 339/75 MP for splicing flat ribbon type cables by using a spacer 3,243,762 3/1966 Tamburro 339/17 LM for holding the cables in proper registry with each other and inserting the spacer and cables into the a 0V6 3,686,612 3/1972 Clements 339/75 MP housmg' 3,825,878 7/1974 Finger 339/176 MF 14 Claims, 13 Drawing Figures 44 g 66 42 86 62 38 E I 43 58 50 25 7;; 3e i g PATENIEDPEB 3,864,012

SHEET 10? 3 PATENIED 4W5 3.864.012

SHEET 20F 3 I I I PATENTED FEB 41975 4 IIIIII/IIIIII i 1 ELECTRICAL CONNECTOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to electrical connectors and more particularly to a connector for forming electrical interconnections between the edge contacts of printed circuit boards and the conductors of a flat multiconductor flexible cable,. and for splicing flat cables.

2. Description of the Prior Art With the ever increasing complexity of modern day electronic equipment systems, it is often necessary to provide interconnection between a great number of printed circuit boards and their components with other related elements of the over-all electronic system. The present techniques employed require that these printed circuit boards may be easily removable from their electrical connectors and mounting devices for rapid change as necessitated by failure of components or over-all circuits and for servicing and testing purposes.

To accomplish these purposes, the systems generally require a number of separate subsystems united into a single unit. Of primary importance is the electrical connector itself which is required to connect individual wires to the conductors of the printed circuit boards leading to the components thereon. These connectors are usually found to have spring loaded fingers to affect the connection between the wires and the conductors of the printed circuit boards. The connectors themselves must be individually wired to the input-output cables or suitably connected to wires of other power and signal supplying means. Due to the trend towards miniaturization of components and related elements, the amount of spacing available in the connectors for such coupling and/or wiring is extremely limited and great care must be taken so as to prevent shorts and other destructive practices with respect to the connector.

In addition, a framework must be provided for supporting the circuit board and this framework must allow the circuit board to be easily removed and reinserted into the connector with no destruction to the connector itself. It has been found in practice that the continual insertion and removal of such printed circuit boards often leads to the weakening of the spring loaded fingers of the connectors such that intermittent connections may occur, and sometimes results in complete failure of the connector.

Recent attempts have been made to eliminate as much as possible, the individual wiring associated with this type of connection, and to eliminate the spring loaded type of finger contacts. These attempts have emloyed a rather recent development in the art, that is,

flat ribbon type flexible cables. These cables generally include a flexible insulative backing having a pattern of flat electrical conductors which are formed by an etching process or the like. Another type of cable employing this basic principle is formed with circular conductors imbedded in insulative ribbon type material. These types of cables have several advantages over conventional wiring such as requiring less room and providing a much easier method for matching of impedances which is necessary with todays high speed electronic equipment.

The flat cables may be coupled directly to the edge contacts of the circuit board and are held in conductive contact by various types of connectors. These prior art connectors are designed to retain the cable in a manner so that the edge connectors of the circuit board may be positioned in abutting contact therewith. Means associated with the connector exerts a compressive force on the cable and the board to hold their respective conductors in electrical contact.

In general, these prior art connectors have proven unsatisfactory for various reasons among which are expense and complexity. Some of these connectors were unable to exert an evenly distributed force over the plural contacts, while others resulted in problems of insertion and removal of the boards.

Therefore, there exists a need for a highly simplified and efficient means to make connections between the ribbon-type cables and circuit boards and for splicing of cables. Solution to this need is basic to the production of truly low cost computers and other electronic devices.

SUMMARY OF THE INVENTION The present invention overcomes many of the difficulties noted with respect to the prior art by providing a simple unitary structure which accomplishes the function of electrically interconnecting multiconductor elements such as one or more flexible ribbon cables with one or more printed circuit boards and/or splicing of the flat cables. The connector also provides a sup porting member for holding the circuit boards in the operating position and provides mounting means to retain the boards in the desired position and yet allow easy removal thereof when desired.

The connector is designed to bring into direct operative relationship the individual conductors of a multiconductor printed circuit board with the individual conductors of a flexible ribbon cable thus eliminating the need for individual wiring of the connector. In the operating position compressive pressure is brought to bear so as to hold the individual conductors of the flexible ribbon cable in contact with the aligned conductors of the printed circuit board to assure intimate contact therebetween, and may provide the same function for splicing of flat cables.

Briefly, the connector of the present invention is provided with a housing which may be fabricated to accommodate one or more printed circuit boards. The printed circuit board is provided with a notch on the side edge which contains the normal edge contacts. The flexible ribbon cable is registered within this notch so that the conductors of the printed circuit board are aligned with the conductors of the ribbon cable. This edge of the printed circuit board having the flexible cable positioned thereon is inserted into an opening formed in the connector housing and upon entering therein will engage a tension band. The tension band is held in a U-shaped configuration and has a pair of movable cams mounted thereon. When the circuit boardribbon cable assembly contacts the tension band, the cams will move towards each other and contact the upper and lower surface of the circuit board adjacent to the edge on which the edge contacts are disposed. The movement of the cams exerts a compressive force which forms electrical interconnections betwen the ribbon cable and the circuit board. The same connector may be employed for splicing flat ribbon type cables by providing a spacer element upon which the cables are placed in an overlapped aligned relationship so that the spacer element and cables may be inserted into the 3 connector in'the same manner as the circuit boardribbon cable. assembly. I

Accordingly, it is an object of the present invention to provide a new and useful electrical connector interconnecting multiconductor elements.

Another object of this invention is to provide a new and useful connector for electrically coupling a'flat ribbon type cable to a printed circuit board.

Another object of the present invention is to provide a new and useful connector for splicing flat ribbon type cables.

Another object of this invention is to provide a new and useful connector into which one or 'more printed circuit boards may be plugably inserted for electrical interconnection with one or more flat ribbon type cables.

Another object of this invention is to provide a new and useful connector for electrically coupling at least one flat ribbon type cable to at least one printed circuit board, the connector having a housing which contains the connecting elements and also provides supporting structure for the printed circuit boards. I

Still another object of the present invention is to provide a new and useful connector of the above described character in which the conductors of the flat cable are held in conductive contact with the, edge contacts of the printed circuit board by cam means mounted on a tension band which exert a compressive force on the contacts when movably activated by engagement thereof by the circuit board-cable assembly.

The foregoing and other objects of this invention, as well as the invention itself, may be more fully understood when read in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary side elevation partially broken away to illustrate the various features of the present invention as being applied to electrically couple flat ribbon type cables to printed circuit boards.

' 1 FIG. 2 is a sectional plan view ofthe connector of the present invention taken on the line 2-2 of FIG. 1.

FIG. 3 is an enlarged sectional view illustrating a modification of the connection elements of the present invention. FIG. 4 is an enlarged sectional view illustrating one embodiment of the connection elements of the present invention in their disengaged and workpiece engaging positions.

FIG. 5 is a view similar to FIG. 4 illustrating a second embodiment of the connection elements of the present invention.

FIG. 6 is a fragmentary side elevation of one embodiment of the cam element of the present invention.

FIG. 7 is a sectional view taken along the line 7-7 of FIG. 6. f

FIG. 8 is a sectional view similar to FIG. 7 and showing a modification of the cam element of the present invention. I

FIG. 9 is a sectional view similar to FIGS. 7 and 8 showing another modified cam element of the present invention.

I FIG. 10 is a sectional view similar to FIGS. 7, 8, and 9 showing yet another modification of the cam element. I

' FIG. 11 is a fragmentary side elevation similar to FIG. 1 but showing the connector of the present inven-.

4 tion as being employed for splicing flat ribbon type cables.

FIG. 12 is a perspective view of a spacer element employed to splice the cables.

FIG. 13 is a fragmentary perspective view ofone type of flat ribbon type cable.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to the drawings, FIGS. I and 2 illustrate a connector I0 of the present invention having a printed circuit board 11 and a flat ribbon type cable 12 inserted therein and held in interconnecting conductive contact as will hereinafter be described in detail.

The printed circuit board 11 is of the conventional type and has the usual rigid insulative backing 14 which upon one or both surfaces thereof is provided the usual conductors 16. The conductors 16 are employed to interconnect the usual components 17 mounted on the board as is well known in the art. The board 11 is also provided with a plurality of edge contacts 18 by which power and signals are coupled thereto.

Although the circuit board 11 as thus far described, is of conventional construction, two modifications may be performed thereon which will enhance its operation with the connector 10 of the present invention.

The first of these modifications is to form a notch 20 in the side of the circuit board which is adjacent to the edge contacts 18. This is accomplished so that when the cable 12 is to be coupled to the board 11, proper alignment thereof is assured.

The second of the modifications which may be performed on the circuit board 11 is to form, such as by drilling, a pair of apertures 21 (one shown in FIG. 2) adjacent to opposite side edges 22 and 23 of the board II. This modification 'is accomplished to provide mounting means such as pins 25 by which the board 11 may be removably mounted to the connector 10 in the proper operational position. 1

The ribbon type cable 12 illustrated is but one typ of several varieties currently being employed, therefore, it should be understood that the connector of the present invention may be used with any of the cables currently known.

Briefly, the cable 12 as seen in FIG. 2, includes an insulative flexible backing 24 upon which a plurality of conductors 26 are formed such as by the well known etching process. The conductors 26 of cable 12 are formed in predetermined patterns and have the distances between centers determined by corresponding distances between the edge contacts 18 of the board 11. This is accomplished not only for alignment purposes but to match impedance of the boards with the cables.

The connector 10 as seen in FIG. I is provided with a housing 28 which may be fabricated to interconnect a single circuit board with a ribbon cable or may be fabricated to accommodate a plurality of such interconnections.

The housing 28 is formed in two halves 30 and 32 which are normally held in a closed position such as by screws 34 that interconnect abutting flanges 33 formed on the housing halves 30 and 32. The housing halves 30 and 32 may be easily opened for assembly and/or servicing purposes by means of a conventional type of piano hinge 35."Also, the housing 28 may be provided mounted to a structural member 39.

The chambers 36 are separated from each other by a first shelf 38 which extends from the wall 40 of the housing half 32 into the interior of the housing 28 and nestingly aligns with but does not contact, a second shelf 42 which has a U-shaped channel 43 in its extending end. The second shelf 42 extends from the wall 44 of the housing half 30. j

The wall 44 of the housing half 30 is provided with an elongated slot 46 through which the circuit board and ribbon cable, to be electrically interconnected, are inserted into the chamber 36. It will be noted that there is one slot 46 for each chamber 36, and such slots are located equidistant between the shelves 38 and 42 which separate the chambers.

Each of the elongated slots 46 are formed with an outwardly extending flange 48 to which is fitted a sealing grommet 50. The grommets are formed of resilient material such as rubber and will close the slots 46 when chamber 36 is not in use for preventing contamination thereof such as by moisture, dirt and the like.

The grommets 50 are formed with an elongated slit 52 so that the circuit board and ribbon cable assembly may be inserted through the slit 52 and by doing so will deflect the lips 54 thereof and create a contiguous engagement between the lips and the circuit board-ribbon cable assembly thus sealing the chamber 36 against contamination.

An elongatedribbondike tension band 56 is suitably secured on its opposite ends 58 (one shown) to the interior of housing half 32 such as by a retainer plate 60 held in place by screws 62. The band 56 is fabricated of an elastic material such as rubber and is mounted so. thatit presents one surface facing the slots 46 and is coextensive therewith.

The band 56 is positioned so that it passes through a gap 64 between each of the nestingly aligned shelves 38 and 42, and contacts the extending ends of each of the shelves 38. The band 56 is suitably secured to each of the shelves 38 at the point of contact such as by screws 66. Thus it may be seen that the band 56 is attached in spaced increments along its length to provide a series of segments 68, each of which is disposed within a different one of the chambers 36. It should also be noted that by mounting the band 56 in this fashion, each segment 68 may be stressed independently and thus will operate independently from its adjacent segments as will be fully described.

A tension pre-load is applied, as will be described, to each segment 68 of the band 56 to form the segments into a substantially U-shaped in cross section configuration with the bight portions 70 thereof being aligned and coextensive with the slots 46 and the leg portions 72 and 73 being divergent with respect to each other. Thus a circuit board-ribbon cable assembly entering into the chamber will contact the bight 70 and force it toward the wall 40. This movement will cause the legs 72 ad 73 to move toward each other, i.e., the included angle becomes smaller, and also causes a stretching of the segment which increases its stress.

A cam means 76 is affixed to each segment 68 adjacent to the bight portion 70 thereof. The cam means 76 as will be described, performs two functions, the first being to assist in the application of the tension preload on its segment 68 and the second is the application of a compressive load on the circuit board-ribbon cable assembly for electrical interconnection thereof. 5

The cam means 76, in one embodiment thereof, in-

nected in a spaced apart relationship by a web 82. Each of the cams 78 and 80 are provided with a longitudinal I slot 84 as best seen in FIG. 4. The tension band 56 is threaded through the slots 84 of the cams 78 and 80 so that the cam means 76 is centrally located along the length of the segment 68. In this position. the web 82 will overlay the bight portion of the segment 68 and thus locate the cam 78 on the leg 72 and the cam on the leg 73.

As seen in the connecting chamber identified as 36a in FlG.l, no circuit board-ribbon cable assembly has been inserted therein, therefore the segment 68 will be urged, due to tension on the segment, toward a straight line position between the ends of the shelves 38. However, the cams 78 and 80 prevent complete straightening of the segment by contacting a tension means which in this embodiment is the extending ends 86 of the second shelf 42. Therefore, it may now be easily seen that the cam means 76 cooperates with the second shelf 42 to pre-load the segment 68 into the substantially U- shaped configuration. I

An alternate tensioning means for pre-loading the segments 68 is illustrated in FIG. 3, wherein the web 82 of the cam means 76 is provided with one or more spacedly positioned tabs 88,which extend through apertures 90 formed in the segment 68. A spring 92 is coupled from each of the tabs 88 to similar tabs 94 provided on the wall 40 thus biasing the segment into the pre-loaded U-shaped configuration as previously described.

The second function performed by the cam means 76 is best described with reference to FIG. 4 of the drawings in which the circuit board-ribbon cable assembly is shown in solid lines at a position of initial contact with the cam means 76, and is shown in dashed lines at a position of full contact or in a working position.

The initial contact position shown in FIG. 4 illustrates the points of contact A and B as occurring on the radiused leading edge 96 of the circuit board-ribbon cable assembly. it will be noted that the distance between points A and B is'somewhat less than the thickness dimension of the circuit board-ribbon cable assembly. Movement of this assembly in the direction of arrow 98 will simultaneously push the bight portion 70 of the segment 68 and cam means 76 toward the dashed line position and will separate the contact points A and B causing them to ride up in a sliding movement over the radiused edge 96 until they arrive at the contact positions identified as points A and B. Due to the separation and pushing movements exerted during insertion of the circuit board-ribbon cable assembly, an increase in the stress of the bight portion 70 and of the leg portions 72 and 73 will occur. The force vectors applied by these portions of the tension band 56 produces a resultant vector which exerts a compressive force on the circuit boardribbon cable assembly to form electrical interconnection between the conductors 26 of the cable 12 and the edge contacts 18 of the circuit board 11.

A modified form of the cam means 76 is illustrated in FIG. 5 and is identified as cam means 76a. in this embodiment, the cam means 760 is seen to be made up only of a pair of cylindrical cams 100 and 102 which are not interconnected by a web such as was the case 76. The cams 100 and 102 of cam means'76a are assembled to the tension band 56 by a threading operation inthe same manner as previously described, however in this case the'cams must be attached to the band 56 to prevent them from sliding along their respective legs 72 and 73 when separating force is applied thereto. The cams 100 and 102 are each provided with a longitudinal slot 104 formed therein which are for thesame purposes as were the slots 84 of earns 78 and 80. It will be noted that the slots 104 are V-shaped in crosssectional configuration to increase the surface friction between the cams and the band 56. This same crosssectional configuration could be employed with the cams 78 and 80, but is not as essential in that embodiment. l

To ensure that the cams 100 and 102 will not slide along their respective legs72 and 73, the cams may be fixidly secured-in the proper positions by the application ofa bonding agent 106 such as epoxy cement.

The cam means 76a will react to the forces applied in a somewhat different manner than that previously described for cam means 76 due to the absence of the web 82.

As seen in FIG. 5, wherein the initial contact is shown in solid lines, an intermediate contact position is shown in dashed lines and a final position is shown in dotted lines, the initial contact points C and D are in the same location as the initial contact points A and B in that they occur on the radiused leading edge 96 of the circuit board-ribbon cable assembly and are spaced apart a distance somewhat less than the thickness dimension of this assembly. Movement ofthe circuit board-ribbon cable assembly in the direction of the arrow 108 will cause the cams 100 and 102 to roll up over the radiused surface 96 in a movement whichdid not occur to any great extent in the cam means 76 due to the restraint applied by the web 82. This rolling movement may be a combination of rolling and sliding movement with the determining factors being interfacial friction of the cams and radiused edge 96 and stress of the band. As seen in the dashed line intermediate position of FIG. 5, the cams 100 and 102 have moved so that the contact points are now located at the points identified as C and D-'. In doing so, it will be noted that the bight 70 of segment 68 has been considerably stretched thus increasing the force applied-to the cams by the bight portion. Also, the same movement of the segment 68 and connector 76a in the direction of the arrow 108 will stretch the legs 72 and 73 and decrease the included angle therebetween. Continued movement of the circuit board-ribbon cable assembly toward the dotted line final position will again decrease the included angle between the cams 100 and 102 and elongate the legs 72 and 73 still further, also this movement will change the bight portion 70 from a straight line between the cams ered with respect to the cross-sectional. configuration of the cams. Placement of the slots in this offset location with respect to the axis of rotation will supplement 8 the compressive forces applied by the cams on the circuit board-ribbon cable assembly.

FIG. 6 illustrates one of the cams in detail and will be" identified as cam 100 for descriptive purposes. It should be noted that the detailed description of cam 1-00 and the modifications thereof, which will hereinafter be described in detail, do not apply to cam100 only, but also apply to cams 78, 80, and 102.

In the preferred embodiment shown in FIGS. 6 and 7, it will be seen that the cam 100 includes an elongated cylindrical body 110 in which the elongated slot 104 is formed with an angular crossectional configuration. A portion of the periphery of cam 100 is formed with an alternating series of land areas 112 having recessed areas 114 interposed therebetween. The distance between the center lines of the lands 112 and their width dimensions are selected to correspond to the dimensions of the edge contacts 18 'of the circuit board 11 and the conductors 26 of the ribbon cable 12, so that the compressive force applied by either cam means 76 or 76a will not be unnecessarily dissipated by being applied to areas where no contact is needed.

As seen in FIG. 7, the cam has an outer coating 116 of insulative compressible resilient material such as rubber which may be. applied thereto by any number of well known techniques. The coating 116 is applied so that the cam 100 will have a high coefficient of friction to enhance the rolling movement and retard the sliding movement as previously described. The coating will also compensate for a dimensional deviation in the thickness of the circuit board-ribbon cable assembly to ensure an even distribution of the forces across all the contacts to be interconnected.

FIG. 8 illustrates a modified cam 100a wherein the coating 116 has been replaced with an elongated pad insert 118 of material similar to that of the coating 116.

FIG. 9 illustrates a cam 10% which is similar to the embodiment illustrated in FIG. 7 except that the periphery of the cam is provided with a cam profile 120 which is designed to increase the tension applied to legs 72 and 73 and the tension applied to the bight portion 70 of the segment. 68.

FIG. 10 illustrates yet another modified cam 100C in which a double cam profile 122 and 124 is formed on the periphery to provide a double point of contact and a snap action during insertion of the circuit boardribbon cable assembly into the connector 10.

Reference is now made to FIGS. 11, 12, and 13 wherein the elements and operation of the connector 10 will be described with relation to the splicing of a pair of ribbon cables 126 and 128.

As seen in FIG. 11, the connector 10 is identical to thatpreviously described and has the cam means 760 mounted therein. In order for the connector 10 to function in its capacity as a cable splicer, there is provided a spacer element 130. The spacer 130 has a flat rigid body 131 of generally rectangular shape with a handle portion 132 on one of its relatively long ends and its opposite end is provided with a notch 134 for the purpose of assuring and maintaining alignment between the cables 126 and 128 to be spliced. The spacer 130 is also provided with mounting means in the form of a pair of apertures 136, one being drilled or otherwise formed adjacent to each of the side edges 138 and 140 of the spacer 130. The removable mounting of the spacer 130 to the connector 10 is identical to that previously described for mounting of the circuit board to the connector and therefore will not be repeated.

it should be understood that any of the well known types of ribbon-like flat cable may be spliced by the connector 10 of the present invention. However. a detailed description of the splicing of a particular type of cable is deemed appropriate.

The cables 126 and 128 are of the shielded type well known in the art and are seen in FIG. 13, wherein the cable 126 is shown, to include a backing 144 of insulative material. Also, an upper ground plane 146 and a lower ground plane 148 are provided which have the conductors 150 interposed therebetween. This type of cable is particularly well suited for applications which require, among other things, impedance matching.

The cable 126 has been prepared for splicing in the connector 10 of the present invention by cutting away portions of the insulative backing 144 to expose the conductors 150 and the laterally disposed surfaces 145 of the upper ground plane 146.

It should be understood that this stripping operation may be performed on a terminal end of the cables as shown or may be in the form of a window (not shown) at any desired location along the length of the cables.

The cable 128 is stripped in an identical manner, and the cables 126 and 128 are positioned in an overlapping relationship as shown in FIG. 11. The compressive forces exerted by the cam means 76 or 76a will electrically interconnect the conductors 150 of the cables 126 and 128 and will also electrically couple the surfaces 145 of the ground planes 146 of cables 126 and 128 to each other.

While the principles of the invention have now been made clear in an illustrated embodiment, there will be immediately obvious to those skilled in the art, many modifications of structure, arrangements, proportions, the elements, materials, and components used in the practice of the invention, and otherwise, which are particularly adapted for specific environments and operation requirements without departing from those principles. The appended claims are therefore intended to cover and embrace any such modifications within the limits only of the true spirit and scope of the invention.

What I claim is:

l. A connector for electrically interconnecting flat multiconductor elements such as a printed circuit board having edge contacts upon which the conductors ofa flexible ribbon cable are aligningly positioned, said connector comprising:

a. a housing having at least one connection chamber formed therein and having an elongated slot formed in one wall thereof which opens into the center of the chamber and through which the portions of the multiconductor elements to be electrically interconnected are insertable;

b. a tension band of elastic material mounted within the chamber of said housing and positioned to present one surface in facing coextensive relatinship with the slot of said housing;

c. tension means within the chamber of said housing for deflectively contacting said tension band to apply a tension preload to said band and to form it into a substantially U-shaped cross-sectional configurationwiththe bight portion thereof aligned and coextending with the slot formed in said housing and the leg portions thereof forming a diverging included angle therebetween which extends from the bight portion toward the slot of said housing. the extending ends of the leg portions being se' cured to said housing so that movement of the bight portion away from the slot is produced by deflective engagement of the multiconductor elements when they are inserted therein which will increase the stress of said band and reduce the included angle between the legs of said band by moving the legs toward each other; and

d. cam means mounted on said tension band and positioned thereon so that a portion of said cam means is disposed on each of the leg portions of said band and movable therewith for applying a compression force to the multiconductor elements when they are inserted into the chamber of said housing, the compressive force resulting from the stress of said band and movement of the leg portions which decreases the included angle therebetween.

2. A connector as claimed in claim 1 wherein said housing is provided with a plurality of connection chambers each separated from its adjacent chambers by a first shelf extending from one wall of said housing and nestingly aligning in a non-contacting relationship with a second shelf extending from the opposite wall of said housing to provide a gap communicating between each of the connection chambers so that said tension band may be formed of a continuous sheet strung through said gaps to present a segment of said tension band within each of said chambers, said tension band being secured along its length to each of said first shelves to operationally isolate each of the segments from its adjacent segments.

3. A connector as claimed in claim 2 wherein said housing is formed of hingedly connected housing halves, a first one of said housing halves having said first shelves formed therein and a second one of said housing halves having said second shelves formed therein, and further including means for securing said housing halves together.

4. A connector as claimed in claim 1 wherein said tension means includes a pair of shelves formed on the wall of said housing in which the slot is formed, said shelves are positioned in a spaced apart parallel relationship on opposite longitudinal sides of the slot and are coextensive therewith, said shelves extending into the connection chamber for deflectively contacting said cam means to apply a tension to said tension band and form it into the U-shaped configuration.

5. A connector as claimed in claim 1 wherein said tension means comprises a tension spring connected to the bight portion of said tension band and to said housing for biasing said tension band into the U-shaped configuration.

6. A connector as claimed in claim 1 wherein said cam means comprises a pair of cylindrical cams each having a longitudinally disposed slot formed therethrough through which said tension band is inserted to assemble said cams in a spaced apart parallel relationship thereon.

7. A connector as claimed in claim 6 wherein said cam means further comprises a flexible web interconnecting said pair of cams.

8. A connector as claimed in claim 6 wherein each of said pair of cams have an alternating series of lands and recesses formed in at least a portion of its longitudinally disposed peripheral surface.

9. A connector as claimed in claim 6 wherein the slot formed in each of'said pair of cams is offset with respect to the longitudinal axisof said cam and formed into a substantially V-shaped in cross-sectional configuration. I

10. A connector as claimed in claim 6 wherein each of said cams is provided with a coating of compressible resilient material.

11. A connector as claimed in claim 6 wherein each of said cams is provided with an elongated pad insert ofcompressible resilient material mounted on its longitudinally disposed peripheral surface. 7

12. A connector as claimed in claim 6 wherein each of said cams has at least one cam profile formed on its longitudinally disposed peripheral surface.

13. A connector for electrically interconnecting flexible flat multiconductor elements comprising:

a. a rigid spacer element upon which the flexible multiconductor elements are overlappingly positionable so that the exposed conductors of one of the flexible elements is aligningly contacting the exposed conductors of the other flexible elements;

b. a housing having at least one connection chamber formed therein and having an elongated slot formed in one wall thereof which opens into the center of the chamber and through which the portions of the multiconductor elements to be electrically interconnected are insertable;

c. a tension band of elastic material mounted within the chamber of said housing and positioned to present one surface in facing coextensive relationship with the slot of said housing;

(1. tension means within the chamber of said housing for deflectively contacting said tension band to apply a tension pre-load thereto and form 'said band into a substantially U-shaped cross-sectional configuration with the bight portion thereof aligned and coextending with the slot of said housing and the leg portions thereof forming a diverging included angle which extends from the bight portion toward the slot of said housing, the extending ends of the leg portions being secured to said housing so that movement of the bight portion away from the slot is produced by deflective engagement of the multiconductor elements when they are inserted therein which will increase the stress of said band and reduce the included angle between the legs of said band by moving the legs toward each other; and

e. cam means mounted on said tension band and positioned thereon so that a portion of said cam means is disposed on each of the leg portions of said band and movable therewith for applying a compression force to the multiconductor elen nts when they are inserted into the chamber of said housing, the compressive force resulting from the stress of said band and from movement of the leg portions toward each other.

14. A connector as claimed in claim 13 wherein said spacer element comprises:

a. a rigid body of generally rectangular configuration;

b. a handle formed on one of the side edges of said body; and

c. a notch formed in the opposite side edge of said body. 

1. A connector for electrically interconnecting flat multiconductor elements such as a printed circuit board having edge contacts upon which the conductors of a flexible ribbon cable are aligningly positioned, said connector comprising: a. a housing having at least one connection chamber formed therein and having an elongated slot formed in one wall thereof which opens into the center of the chamber and through which the portions of the multiconductor elements to be electrically interconnected are insertable; b. a tension band of elastic material mounted within the chamber of said housing and positioned to present one surface in facing coextensive relatinship with the slot of said housing; c. tension means within the chamber of said housing for deflectively contacting said tension band to apply a tension preload to said band and to form it into a substantially Ushaped cross-sectional configuration with the bight portion thereof aligned and coextending with the slot formed in said housing and the leg portions thereof forming a diverging included angle therebetween which extends from the bight portion toward the slot of said housing, the extending ends of the leg portions being secured to said housing so that movement of the bight portion away from the slot is produced by deflective engagement of the multiconductor elements when they are inserted therein which will increase the stress of said band and reduce the included angle between the legs of said band by moving the legs toward each other; and d. cam means mouNted on said tension band and positioned thereon so that a portion of said cam means is disposed on each of the leg portions of said band and movable therewith for applying a compression force to the multiconductor elements when they are inserted into the chamber of said housing, the compressive force resulting from the stress of said band and movement of the leg portions which decreases the included angle therebetween.
 2. A connector as claimed in claim 1 wherein said housing is provided with a plurality of connection chambers each separated from its adjacent chambers by a first shelf extending from one wall of said housing and nestingly aligning in a non-contacting relationship with a second shelf extending from the opposite wall of said housing to provide a gap communicating between each of the connection chambers so that said tension band may be formed of a continuous sheet strung through said gaps to present a segment of said tension band within each of said chambers, said tension band being secured along its length to each of said first shelves to operationally isolate each of the segments from its adjacent segments.
 3. A connector as claimed in claim 2 wherein said housing is formed of hingedly connected housing halves, a first one of said housing halves having said first shelves formed therein and a second one of said housing halves having said second shelves formed therein, and further including means for securing said housing halves together.
 4. A connector as claimed in claim 1 wherein said tension means includes a pair of shelves formed on the wall of said housing in which the slot is formed, said shelves are positioned in a spaced apart parallel relationship on opposite longitudinal sides of the slot and are coextensive therewith, said shelves extending into the connection chamber for deflectively contacting said cam means to apply a tension to said tension band and form it into the U-shaped configuration.
 5. A connector as claimed in claim 1 wherein said tension means comprises a tension spring connected to the bight portion of said tension band and to said housing for biasing said tension band into the U-shaped configuration.
 6. A connector as claimed in claim 1 wherein said cam means comprises a pair of cylindrical cams each having a longitudinally disposed slot formed therethrough through which said tension band is inserted to assemble said cams in a spaced apart parallel relationship thereon.
 7. A connector as claimed in claim 6 wherein said cam means further comprises a flexible web interconnecting said pair of cams.
 8. A connector as claimed in claim 6 wherein each of said pair of cams have an alternating series of lands and recesses formed in at least a portion of its longitudinally disposed peripheral surface.
 9. A connector as claimed in claim 6 wherein the slot formed in each of said pair of cams is offset with respect to the longitudinal axis of said cam and formed into a substantially V-shaped in cross-sectional configuration.
 10. A connector as claimed in claim 6 wherein each of said cams is provided with a coating of compressible resilient material.
 11. A connector as claimed in claim 6 wherein each of said cams is provided with an elongated pad insert of compressible resilient material mounted on its longitudinally disposed peripheral surface.
 12. A connector as claimed in claim 6 wherein each of said cams has at least one cam profile formed on its longitudinally disposed peripheral surface.
 13. A connector for electrically interconnecting flexible flat multiconductor elements comprising: a. a rigid spacer element upon which the flexible multiconductor elements are overlappingly positionable so that the exposed conductors of one of the flexible elements is aligningly contacting the exposed conductors of the other flexible elements; b. a housing having at least one connection chamber formed therein and having an elongated slot formed in one wall thereof which opens into the center of the chamber And through which the portions of the multiconductor elements to be electrically interconnected are insertable; c. a tension band of elastic material mounted within the chamber of said housing and positioned to present one surface in facing coextensive relationship with the slot of said housing; d. tension means within the chamber of said housing for deflectively contacting said tension band to apply a tension pre-load thereto and form said band into a substantially U-shaped cross-sectional configuration with the bight portion thereof aligned and coextending with the slot of said housing and the leg portions thereof forming a diverging included angle which extends from the bight portion toward the slot of said housing, the extending ends of the leg portions being secured to said housing so that movement of the bight portion away from the slot is produced by deflective engagement of the multiconductor elements when they are inserted therein which will increase the stress of said band and reduce the included angle between the legs of said band by moving the legs toward each other; and e. cam means mounted on said tension band and positioned thereon so that a portion of said cam means is disposed on each of the leg portions of said band and movable therewith for applying a compression force to the multiconductor elements when they are inserted into the chamber of said housing, the compressive force resulting from the stress of said band and from movement of the leg portions toward each other.
 14. A connector as claimed in claim 13 wherein said spacer element comprises: a. a rigid body of generally rectangular configuration; b. a handle formed on one of the side edges of said body; and c. a notch formed in the opposite side edge of said body. 